Apparatus for making rope strand or yarn



May 17, 1966 J. STIRLING APPARATUS FOR MAKING ROPE STRAND OR YARN 2 Sheets-Sheet 1 Original Filed May 13, 1963 SINGLES OF PLiED YARN 23 INVENTOR.

'' James Srirfling ATTORNEY y 7, 1966 J. STIRLING 3,251,178

APPARATUS FOR MAKING ROPE STRAND OR YARN Original Filed May 15, 1963 2 Sheets-Sheet 2 m I 6 l!) 4 0 m o if) FIG.6

United States Patent 3,251,178 APPARATUS FOR MAKlNG ROPE STRAND OR YA James Stirling, 109-26 209th St., Queens Village, Long Island, NY.

Original application May 13, 1963, Ser. No. 279,736, now Patent No. 3,201,930, dated Aug. 24, 1965. Divided and this application Apr. 23, 1965, Ser. No. 451,101

6 Claims. (Cl. 57-15) This is a division of my copending application Serial No. 279,736, filed May 13, 1963, now U.S. Patent No. 3,201,930, which in turn is a continuation-in-part of application Serial No. 827,515, filed July 16, 1959, now U.S. Patent No. 3,097,472.

This invention relates in general to a rope strand construction, and to a method and apparatus for making the same. More particularly the invention relates to an improved rope strand made of either natural and/ or synthetic fibers specifically constructed so as to insure that each of the individual fibers in the finished strand is substantially equal in length per unit length of strand when the same material is used so that each fiber is uniformly stressed when loaded, and including the method and apparatus for making the same. The invention further contemplates an improved strand construction as described wherein dissimilar material either natural and/or synthetics are used wherein the lengths of the individual fibers are controlled by taking in consideration the known elastomeric properties of the different materials used so that the individual fibers will be more uniformly stressed under load.

It has been observed upon many observations and close examinations that ropes of conventional construction fail for the most part in one strand which is broken to destruction while the other strands usually have several of the inside or core yarns pulled out to destruction, with the cover yarns showing no signs of any appreciable damage. The extent of damage resulting from such breaks of course depends on the specific construction of the rope, e.g. with regard to the twist of the yarn, the lay of the strand, the lay of the rope, the fore-hard, and the tension during manufacture. However the indications are evident that failure of the present day rope construction is due to the load being unevenly distributed over each strand, and over each of the individual ends or yarns therein.

In considering for example a three strand manila rope of 5" circumference, such rope normally requires 50 ends or fibers of No. 18 yarn (270 ft./lb.) in each strand. If 290 lbs. is taken as the breaking strain for this size yarn, it will be noted that 3 strands x 50 ends x 290 lbs. per end equals 43,500 lbs., or the theoretical breaking strain for such rope. However, the required minimum break for such 5" circumference 3 strand manila rope according to Federal Specification TR 605 is 22,500 lbs. or approximately 48% less than the 43,500 lbs. These facts are well-known to ropemakers, but very little has been done to reduce this loss in strength. It is possible to achieve relative equality of yarns in a strand structure by using groups of twisted yarns in the form of a strand structure or even a rope structure and using these in finished strand construction. But this method and the other known methods have the disadvantage of necessitating additional operations with the resultant increase in cost or decrease in production. This disadvantage is serious enough to offset any improvement that might result in achieving equal yarn lengths in the strand structure. Furthermore, the twisting of groups of yarn to form units for the strand structure will result in increased shear stresses which will also offset the advantages that should 3,251,178 Patented May 17, 1966 be obtained by making the yarns in the strand substantially equal.

A further examination of a piece of finished 5" circumference manila rope of standard lay and conventional construction will reveal that the individual yarns in the strand vary in length overthe length of the finished rope approximately as follows:

The outside cover yarns, plus 32.3%; The second cover yarns, plus 26.2%; The core cover yarns, plus 24.1%; And the core yarns, plus 23%.

As a result of the variance in the lengths of the yarns in the respective layers of a rope strand, the maximum pull on the strand is taken by the inside or core yarn when a load is applied to the strand.

The above percentages of length of course will vary with the difierent materials used, but in all cases where the rope strand is made in accordance with known constructions, there will be a considerable variance in the length of the fibers in the respective layers of the strand, i.e. the cover yarns will be longer than the core yarns. Usually a piece of such rope when broken in a test machine will break in one strand. If the rope strand is made of natural fibers, e.g. manila or sisal, examination of the remaining unbroken strands will show several of the core yarns broken into short powdery lengths while the cover yarns show very little sign of damage, indicating that the core yarns, being shorter, are carrying more than their share of the load.

If synthetic fibers make up the rope strand, there will be evidence of fusing in the core yarns.

Such inherent latent weakness in a rope of conventional or heretofore known construction can and has resulted in serious situations. For example, such ropes when used as ship mooring lines are repeatedly subjected in rough weather to stresses which are just under the breaking stress of the rope, and therefore become internally weakened. With the exception of a little external fusing and chafing at the chocks, capstan and other points of contact, the very real damage to the core yarns cannot be readily noticed. The results attributed to such rope failure thus become obvious.

Therefore, an object of this invention is toprovide a rope construction employing either natural and/or synthetic fibers in which the lengths of the respective individual fibers, yarns, cords, or ends making up the rope strand are rendered substantially equal in length when the same material is used throughout the construction so that each yarn will be uniformly stressed under a given load condition.

Another object is to provide an improved rope strand construction formed of dissimilar synthetic fibers, ends or yarns in which the physical properties of the respective synthetic fibers are utilized together with the controlled lengths of the fibers in the core and the respective layers of the strand to eifect the necessary stretch or elongation to compensate for any variations in the lengths of the respective individual synthetic yarn making up the rope strand.

Another object is to provide an improved method of forming a rope element in which all the individual fibers, yarns, cords or ends are twisted and layed with respect to one another so as to assure that the respective lengths of the individual yarns are substantially equal per unit length of strand when the same material is used.

Another object is to provide an apparatus for controlling and varying the twist of the respective layers of yarn making up a strand of rope so as to assure that the lengths of the individual yarns in each of the layers are made to Another object is to provide a rope making machine which controls the pitch at which the fibers of the same material are twisted per unit length of rope whereby the twist of the respective layers of fibers from the core to the outermost layer of the strand is progressively decreased so that in a finished strand the respective fibers of the core and of each of the succeeding layers are substantially equal in length for insuring uniform stressing of the re spective fibers under given load conditions.

Still another object of the invention is to provide a machine in which the loss in strength of all types of ropes of either natural or man-made fibers made thereby is reduced to a minimum.

Still another object is to provide an apparatus for making an improved strand of rope that is relatively simple in construction, relatively inexpensive to fabricate and positive in operation,

' A further object is to provide a machine for achieving a balanced rope strand construction.

The above objects, features and other advantages are attained by a rope strand or rope element which may be constructed of either natural and/or synthetic fiber, yarns, cords or ends. In accordance with this invention the improved rope strand or rope element is specifically constructed so that the respective ends, fibers, yarns or cords which make up the same are maintained at a controlled length per unit length of finished strand or element so as to result in each of the respective fibers or yarns being able to take its equal share of the load when the rope strand is subjected to a stress for obtaining either maximum strength or for achieving maximum service at whatever load applied. In general the rope strand or rope element construction comprises a core, and at least one or more concentrically disposed layers of yarns or fibers respectively twisted in successive layers onto the core. The arrangement is such that the core and each of the succeeding layers of yarn or fibers layed thereon are twisted either all in the same direction, or the respective layers may be alternately twisted in opposite directions. In either event the specific construction is such that the pitch of the respective layers is varied so that the pitch of each layer including the core is progressively adjusted from the core to the outermost layer of strand. Accordingly, for optimum strength, the yarns of the strand structure and the fibers of the respective yarns in said strand structure are similarly layed into their respective element.

In a modified strand or yarn construction formed entirely of synthetic fibers, the core and the one or more layers twisted about the core are respectively formed of dissimilar synthetic material. In accordance with this invention the synthetic fiber material having the greatest working elasticity is utilized for the core, and other dissimilar synthetic material or materials having preferably progressively less working elasticity are utilized for the respective succeeding layers twisted about the core. The arrangement of this modification is such that the physical properties of the respective dissimilar material are utilized to effect the necessary relative stretch or elongation, when the strand so constructed is stressed, to compensate for any variations in the lengths of the respective individual synthetic yarn or fibers that make up the strand or element. For greater effect, the twist of the respective layers of synthetic yarn or fibers may likewise be varied so that the pitch of the respective layers of synthetic fibers is progressively adjusted or controlled from the core layer to the outermost layer sothat all fibers are more uniformly stressed at a given load.

The method for forming the rope strand in accordance with this invention comprises essentially twisting a plurality of yarn, either of natural or synthetic fibers, to form a core, and twisting other like or dissimilar yarns about the core layer to form thereon one or more succeeding concentrically disposed layers, and progressively adjusting the pitch of the yarn in each of the layers from the core to the outermost layer so that the fibers in each bins of one of the table units may be pulled coaxially through the center of the next succeeding table unit whereby the yarns drawn from the bobbins of the latter table unit are twisted onto the yarn drawn'from the former unit. The arrangement is preferably such that the number of table units coaxially arranged is equal to one less than the number of layers which make up the finished strand. Accordingly, the yarns for the outermost or covering layer are drawn from bobbins carried by a stationary support or creel. The means for drawing the yarns from the respective bobbins and for forming the same onto the strand formed by the table units comprises a fiyer of conventional construction.

In accordance with this invention means are provided for independently controlling and varying the speed and direction of rotation of the respective table means and fiyer with respect to one another so as to give the correct number of turns or pitch to each of the respective yarn layers so that in the finished strand the yarns of the respective layers are rendered substantially equal in length when the same material is used, or adjusted to the correct length in relation to the known elastomeric property of the dissimilar materials used. As a consequence, the finished strand comes very close to having each yarn or cord therein assume an equal share of the load applied thereto. If desired, by suitable gearing in the drive means, the respective table means may be rotated all in the same direction, or alternate table means may be rotated in opposite direction, or in any desired combination thereof.

A feature of this invention resides in the provision wherein the respective bobbin carrying table means and the fiyer are independently controlled to vary the twist of the respective yarns accordingly in each of the layers making up the rope strand so that the respective lengths of the fibers or yarns, per unit length of finished strand, are rendered substantially equal in length when the same material is used, or adjusted to the correct length in relation to the known elastomeric properties of the dissimilar materials used.

Other features and advantages Will become more readily apparent when considered in view of the drawings and description in which:

FIGURE 1 shows a piece of three strand rope with one strand marked oif to show the general pattern of an individual cover yarn.

FIGURE 2 is an enlarged cross-section of the rope taken along line 2-2 of FIG. 1.

FIGURE 3 illustrates a piece of three strand rope in which the lays of the respective individual components thereof are emphasized.

FIGURE 3A is a modified showing of a strand formed with 3 ply yarn with Z twist made of 3 singles of S twist.

FIGURE 4 illustrates an individual rope strand as made in accordance with this invention with the yarns or ends removed to show the core of the strand, one layer of cover yarn for the core, and an outside cover yarn. P

H P P identify the pitch or lay of each layer to illustrate the progressive increase in the twist per unit length of the respective layers from the outermost layer to the core so as to equalize the respective lengths of all the yarns when the strand is layed into finished rope.

FIGURE 5 illustrates a side elevation view of a machine for making the rope strand of this invention.

FIGURE 6 is a partial plane view of FIG. 5.

FIGURE 7 is a partial vertical sectional view taken along line 77 of FIG. 6.

FIGURE 8 is an enlarged detail view of the yarn tensioning means.

FIGURE 9 is a side view of FIG. 8.

Referring to the drawings, FIG. 1 illustrates a length of rope 20 embodying the improved rope strand construction of this invention. The illustrated length of rope 20 is made up of three strands 21, 22, 23. The individual strands of rope 20 can be readily produced on the machine illustrated in FIGS. 5 to 7, which will be hereinafter described. The rope 20 of FIG. 1 is shown with strand 22 marked off as indicated at 24 to show the general pattern of the individual cover yarns. Accordingly,

the outside cover yarn'24 is shaded darker to illustrate how it shows up on the outside and travels in a spiral around the outside of the strand going to the inside of the rope and reappearing on the outside again in a distance approximately equal to the lay of the rope.

' FIGURE Z illustrates the cross section of the rope 20. It will be noted that each of the respective strands 21, 22 and 23 comprises a core 21A, 22A, 23A and a plurality of concentrically disposed layers which includes an intermediate layer 21B, 22B, 23B and an outermost cover layer 21C, 22C, 23C. Each of the respective layers are formed of several ends, fibers or yarns. While only one intermediate layer is shown, it will be understood that more than one intermediate layer may be provided depending upon the size of rope desired.

FIGURE 3 illustrates, for an example, a rope construction in which the respective direction of twist of the individual rope components, making up the rope, are emphasized. -In the example it will be noted that the three strands 21, 22, 23 are twisted so that they slope upwardly and to the right to define a right or Z twist as it is normally referred to in the art. For illustrative purposes a Z is superposed on the lay of-the strands 21, 22, 23. Accordingly, the yarns in the cover or outermost layer of each of the respective strands are layed so they slope upwardly and to the left with a left or S twist or lay. This is indicated by the S formed in strand 21. It will be noted that if the respective layers are formed of single yarns, then the respective single yarns are twisted or layed with a twist which is opposite to that of the layer which includes it. For example if the outer cover is formed of single yarns and individual ends therein are layed with a left twist, the twist of the individual single yarns making up the outer cover layer is to the right or Z twisted. This is shown in FIG. 3 at 25 where cover yarn 21C of strand 21 is magnified.

If the respective layers of the strand are formed of plied yarn as indicated at 2e, FIG. 3A, and as disclosed in a US. patent to D. Himmelfar-b et al. No. 2,971,321, then the plied yarn 26 which makes up the respective layers is twisted in a direction opposite to that which the yarn in the given layer is layed, with the singles of plied yarn 27 being twisted in the direction opposite to the twist or lay of the plied yarn. For example, if the cover layer 21C was formed of a plurality of plied yarns, and the cover yarns were twisted with a left or S lay, as shown in FIG. 3, then the individual plied yarns 26 are plied to the right with a Z twist, whereas the individual singles of said plied yarn 27 are formed with a left or S twist. Thus it will be noted that the twist of the individual yarns in each of the respective layers of the strand is always opposite that of the layer which includes the same.

FIGURE 4 illustrates a further detail of construction. In accordance with this invention the twist, i.e., number of turns per unit length, of the yarn which make up the respective layers of each strand is varied in a particular relationship so as to insure that in a finished strand the respective yarns of each layer are rendered substantially uniform in length. Referring again to FIG. 4, portions of the yarns or ends are removed to show the core layer 21A of the strand 21, the core cover yarn 21B, and the outside cover yarn 21C. P P and P illustrate the pitch or lay of the yarns in the respective layers which make up the strand, and thus it is evident the twist per unit length of the successive layers is progressively increased toward core 21A. The arrangement thus described will serve to balance the respective lengths of all the yarns when the strand is laid into a finished rope.

The method of making an improved strand of rope in accordance with this invention comprises the steps of progressively twisting a plurality of threads, cords or ends to form a core layer with a predetermined pitch or number of turns per unit length, and successively twisting of a plurality of other cords or ends in concentric layers about the core layer so that the pitch of the next core covering layer is greater than the pitch of the core layer and so on, so that in a finished strand of unit length the cords or ends in each of the respective layers are substantially equal in length when the same material is used whereby each end may be uniformly stressed when a load is applied thereto. In accordance with this method two or more layers of fibers may be concentrically twisted one layer upon the other wherein the twist or number of turns per unit length of each succeeding layer from the outermost layer to the core layer is progressively increased. Also, it is contemplated that the respective succeeding layers may be twisted either in the same direction or opposite direction. It is also noted that the method described is equally applicable to making rope strand of synthetic fibers, as well as of natural fibers.

In the making of rope of synthetic fibers, this invention further contemplates the utilization of the physical properties of the respective synthetic fibers, making up the rope strand, to effect the relative proportional elongation of the rope yarns or fibers so that each is made to the correct length in relation to the known elastomeric properties of the dissimilar materials used so that each fiber will be more evenly stressed under a given load. The above concept may be utilized either separately or in conjunction with the method above described.

The common synthetics used in rope making are polyamide fibers nylon, polyester fibers, polyethylene, polypropylene multi filament, polypropylene monofilament. These materials have distinct physical properties, i.e. each has distinct rates of permanent elongation, working elasticity, melting temperatures, and relative strength. For example, assuming a normal load of 30% of ultimate breaking stress and a conventional rope construction the synthetic fiber material listed below evidenced the following characteristic:

Permanent Working Melting Material Elongation, Elasticity, Temp,

percent percent F.

Polyamide fibers-nylon 13 23 About 430. Polyester fibers 12 9 About 500. Polypropylene (multi-filament) 15 14 About 350. Polypropylene (mono-fil) 11 13 About 350. Polyethylene 9 10 About 265.

The relative strength of the above material for a 6" circumferential rope based on average breaking strength in pounds is:

Polyamide fiber-nylon 91,000 Polyester fiber 61,300 Polypropylene multifilament 59,000 Polypropylene monofilament 53,000

and the cover of polyester fibers. Nylon or polyamide fibers in the core will, because of the inherent characteristics thereof, take on more twist without any serious reduction in its strength, and will stretch more than the other synthetic fibers listed. A very fine multi-filarnent polypropylene will also take considerable twist and stretch. Polypropylene monofilamcnt will not take as much twist as the finer multi-filament but it will take more twist than polyester. For this reason polypropylene monofilament is used in the second cover layer where an intermediate amount of twisting is required in accordance with this invention. Also polypropylene monofilament will stretch more than the polyester fiber. Polyester fiber which should take less twist and less stretch is employed in the outermost or cover layer 'where the requirements for twist and stretch are lea-st required in a rope construction of this invention.

In the synthetic rope construction using a combination of the different synthetic fibers discussed above, it will be noted that the melting point and resistance to fusing of the respective fibers is also taken into consideration to result in the rope construction capable of obtaining the most optimum results. In accordance with this invention, for example, polyester fibers which has a melting point of about 500 F., when coupled with its relatively low percentage of working elasticity forms an optimum cover for the rope as it can take greater stress and pressure at the bilts. Thus it has the wear qualities, i.e. its resistance to abrasion and fusion, which will materially enhance the useful life of such rope construction. From the foregoing it will be readily apparent that the concept hereinbefore described of maintaining the stresses and ultimate length of the individual fibers of the same material substantially equal when loaded can be also closely approached by a proper selection of the synthetic fibers and placing them in accordance to their physical properties relative to one another so as to obtain the optimum results. If desired the same considerations can be applied when making rope strand utilizing a combination of natural and synthetic fibers. For optimum results it is necessary to adjust the pitch of the core and the respective layers in the strand structure in relation to the known elastomeric properties of the different materials used in the core and the respective layers so that the individual fibers will be more evenly stressed under a given load.

While the respective rope construction and method of making the same hereinbefore described can be performed by hand, it is preferred that the same be automatically performed at relative high speed by the following described apparatus.

Referring to FIGS. to 7, the apparatus for making rope strand as above described comprises a plurality of rotatably journalled bobbin carrying table means 31, 32. Each of the table mean-s 31, 32 are substantially similar in construction and therefore the detail description of one is considered sufficient to understand the arrangement thereof. Each table means 31, 32 includes a pair of spaced apart upright stanchions 33, 34 provided with a bearing boss 33A, 34A at the upper ends thereof. A flanged bearing 35, 36 having a bore 35A, 36A extending therethrough is rotatably journalled in each of the bearing bosses 33A, 34A. Connected to the flange of the respective bearings 35, 36 is a table plate 37, 38, respectively, which is preferably of circular configuration. In the illustrated embodiment an intermediate table plate 39 is spaced in coaxial relationship to plates 37 and 38. The respective plates are maintained in spaced relationship by the bolts 40 extended through suitable sleeve spacers 41 disposed between adjacent table plates. Bobbins 42 supplying yarn for making the rope strand are mounted between adjacent pairs of plates. As seen the bobbins 42 are circumferentially spaced around the table plates. In the illustrated example each table plate is sized to take 48 8 x bobbins,

24 between each of spaced adjacent plates 37, 39, and 39, 38. While the table unit illustrated is made up of three spaced plates 37, 38, and 39, it will be understood that the same may be made with more or less numbers of spaced plates, the number of spaced plates being determined by the number of bobbins to be carried by the table unit. With the specific table unit construction described, it will be noted that the physical dimensions of the table plates can be controlled within practical considerations by varying the number of table plates.

In accordance with this invention, if an intermediate table plate 39 is utilized, it is provided at its center with a yarn guide 43. As shown the yarn guide 43 comprises 1 a flanged hub 43A formed with a connected cylinder portion 43B. Accordingly guide holes 45 are formed both in the cylinder portion 43B and in the hub of guide 43 respectively, to guide the yarn drawn from the bobbins disposed between plates 38, 39. The outermost plate 37, in the direction in which the yarn is being drawn, is also provided with a similar constructed guide 46. However, guide 46 is formed integral with bearing 35. Located centrally of the guide 46 is a compacting tube 47 which serves to compact the yarns being drawn from the respective bobbins 42 carried by the table unit. It will be noted that the size or diameter of the respective compacting tubes 47 in each of the table units is varied so as to accommodate the yarn or ends being drawn therethrough.

. In the illustrated embodiment only two table means 31, 32 as above described are shown. However, it will be understood that the number of table means can be varied depending upon the number of layers and size of the rope strand which is to be formed. It will also be noted that in accordance with this invention the number of table means provided is preferably one less than the number of yarn layers required to make a given rope strand. This is because in accordance with this invention the outermost or cover layer of a given rope strand is provided by bobbins 48 which are carried on a stationary creel means 49.

The creel means 49 comprises essentially a stationary frame on which are mounted the several bobbins 48 from which the yarn for the covering layer is drawn. Accordingly the covering yarns from bobbins 48 are threaded through suitable creel yarn guide means 50 and tensioning means 50A to guide plate 51 from whence the covering yarn is passed through the compacting tube 52 and twisted onto the strand portions being drawn from the table units 31 and 32. As best shown in FIGS. 8 and 9, the tensioning means 50A comprise a series of tensioning rods 50B, 50C, StlD which extend laterally of the creel part or frame. The respective tensioning rods 50B, 50C, and 50D of each tensioning means 50A are fixed relative to one another, and to the creel frame, as shown. Thus the respective yarn, cord, or fibers are guided under rod 503, over rod 5tlC and under rod 50D in passing from the guides 50 to the guide plate 51. In this manner, the tensioning means serve to straighten out any cockles in the yarns passing thereover so that it will appear smooth and regular in the cover. The amount of tension used is that amount suflicient to keep the cover yarns straight.

As it will be seen in FIG. 5, the means for drawing the yarn from the respective bobbins comprises a fiyer 55 of well-known construction to those skilled in the art. Essentially it comprises a frame 56 which is rotatably jour- H nalled between supports 57 and 58. A take-up reel 59 for receiving the finished rope strand is journalled between the sides of the frame. Associated in driving relationship with the reel by a gear train 60 is a traverse screw means 61 for properly positioning the strand on the reel 59.

The fiyer also includes a gear and capstan assembly 62 about which the finished strand is wound. As shown the fiyer 55 is rotated through a fiyer gear 63 which is driven by a spur gear 64, which is connected to the main drive shaft through an idler gear 65. A gear train including gears 66, 67, 68 serve to drive the capstan assembly 62 as the fiyer 55 is rotated.

In accordance with this invention a feature resides in a drive means for individually controlling the speed and the direction of rotation of the respective table units 31, 32 and the fiyer 55 with respect to one another so that the twist or pitch of the yarn making up the respective layers of the rope strand can be controlled with a relatively high degree of accuracy. Thus by varying the pitch or lay of the respective layers in 'a predetermined manner, the respective yarn or ends in each layer of the rope strand are maintained substantially equal in length when stressed.

In accordance with this invention the drive means comprise a motor 70 which is connected in driving relationship through V pulleys 71, 72, belt 73 and connected driving bevel gear 74 to a shaft 75. As seen in FIG. 6, the driving gear 74 is coupled to the pulley 72. The drive shaft 75 has connected thereto a pair of gears 76, 77 which are arranged to selectively mesh with the bevel driving gear, depending on the direction of rotation desired. As shown the main drive shaft 75 is rotatably journalled in suitable bearings 78 and 7% It will be noted that gears 76 and 77 are longitudinally splined and adjustable along the driving shaft 75 so that when gear 76 is meshing with bevel gear 74 the shaft rotates in one direction, and when gear 76 is disengaged and gear 77 engaged with gear 74, the shaft is rotated in the opposite direction.

Connected to one end of shaft 75 is the spur gear 64 which drives the fiyer 55 in a given direction through an idler gear 63. The respective table units are individually controlled by respective gear trains 80 and 81 as to direction and speed of rotation, the respective gear trains being driven by shaft 75. For reasons of clarity of showing, the drive shaft has been shown at a lower elevation. Therefore, in practice spur gears 82, 83 keyed to shaft 75 are disposed in engaging or meshing relationship with gear trains 80, 81 respectively. The respective gear trains 80, 81 comprise meshing gears 80A, 80B, 80C, 80D and 81A, 81B, 81C, SltD which are respectively mounted on swing arms 84, 85. The arrangement is such that the last gear in the respective gear train 8tlD, 81D meshes with an idler gear 86, 87, respectively, which in turn meshes with a spur gear 88, 89, respectively, keyed to the flanged bearing 36 of the respective table units.

According to this invention the ratio of the respective gear train 80, 81 is such that the speed and direction of the table rotation can be varied relative to each other and to that of the fiyer 55. Thus by suitable gearing ratios the speed and direction of the respective table means and that of the fiyer can be individually controlled and established. Thus the relative angular speed of the respective table means and that of the fiyer attains a result in which the ends or yarns in the finished strand are maintained substantially uniform or equal in length, which is required when the same material is used. The gear ratio can be changed to give the correct twist to the respective stages of the strand stlucture when dissimilar materials are used so that the pitch of the core and the respective layers in the strand structure is adjusted in relation to the clastomeric properties of the respective materials used.

If desired gears of the respective gear trains may include a change gear which can be readily interchanged so as to vary the angular speeds of a given table unit controlled thereby at will. Therefore, from the foregoing description it will be readily apparent that the twist, i.e. number of turns per given unit length of the respective strand layers will vary in accordance with the relative angular rotation of the respective table units and the fiyer. In the illustrated embodiment the ratios or the gear trains are calculated so that the pitch of the respective layers increases progressively from the core to the outermost layer, as best seen in FIG. 4, i.e. twist per unit length of the respective layers of yarn from the core to the outermost layer of the strand is progressively decreased so that in the finished strand the individual yarns of the same material of the respective layers are substantially equal in length, and thereby each yarn is able to carry substantially its equal share of the load when stressed. By changing the gear ratio, the necessary adjustment to the lengths of the yarn in the core and in the respective layers of the strand structure can also be achieved to utilize the respective known elastomeric properties of the different materials used so that the respective fibers will be more uniformly stressed at a given load. From the results of tests made for singles yarn and for strand, and for rope where the singles yarn and the strand were made as herein described all elements in the rope structure showed increased strength, less stretch, longer life and also increased productivity. In accordance with this invention, the pitch of the cover layer of yarn in the strand is longer than the pitch of the cover layer of an equally sized strand conventionally made even though both strands are equally compacted. This will hold true in regard to fibers in the single yarns or the singles of plied yarn so that the end result is increased production in addition to the other improvements in the physical characteristics thereof.

While the instant invention has been disclosed with reference to a particular embodiment thereof, it is to be appreciated that the invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be, made without departing from the spirit or scope of the invention.

What is claimed is: i

1. A machine for making rope strand comprising a plurality of table means, each of said table means having a bearing support with a bore extending therethrough,

. means for rotatably journaling each of said table means in coaxial alignment, a plurality of bobbins having fiber windings thereon mounted on each of said table means, each of said table means including means for guiding the fiber from its respective bobbins through the bore in the bearing support thereof, means for drawing the fibers through the bore of the respective bearing supports so that the fibers drawn from one table means are laid onto the fibers drawn from the next preceding table means, means for rotating each of said tables to impart a twist to the fibers being drawn from the respective bobbins so that the fibers drawn from one of said tables are twisted to form the core of said strand, and the fibers drawn from said other tables are twisted in successive concentric layers upon said core, means for individually controlling the relative rotation and direction of rot-ationof the respective table means with respect to one another to control the pitch at which the fibers drawn from the bobbins of the respective tables are twisted per unit length of rope strand (formed thereby, a stationary creel means, a plurality of creel bobbins containing the fibers for forming the outermost covering layer mounted on said stationary means, means for twisting the fibers from said creel bOl bins onto the strand being formed from the respective table means, and means for controlling the twist in the fibers of said outer covering layer relative to the repective twists imparted to the core and the intermediate layers laid thereon so that the twist in the layers from the core to the outermost covering layer of the strand is progressively decreased so that in the finished strand the respective fibers of the core and of each succeeding layer are substantially equal in length for insuring that each of the fibers are uniformly stressed under given load conditions.

2. A machine for making rope strand comprising a plurality of table means, each of said table means having a bearing support with a bore extending therethrough, means for rotatably journaling each of said table means in coaxial horizontal alignment, a plurality of bobbins having fiber windings mounted on each of said table means, each of said table means including means for guiding the fibers drawn from its respective bobbins through the bore of its respective bearing support, drawing means for drawing the fibers through the bore of the respective bearing support so that the fibers drawn from one table means are laid onto the fibers drawn from the next preceding table means, drive means for rotating each of said tables to impart a twist to the fibers being drawn from the respective bobbins so that the fibers drawn from one of said tables are twisted to form the core of said strand, and the fibers drawn from said other tables are twisted in successive concentric layers upon said core, means for individually controlling the relative rotation and direction of rotation of the respective table means with respect to one another to control the pitch at which the fibers drawn from the bobbins of the respective tables are twisted per unit length of rope strand termed thereby, a stationary creel means, a plurality of creel bobbins containing the fibers for forming the covering layer mounted on said stationary means, said drawing means drawing fibers from said creel bobbins simultaneously with the drawing of the fibers from said tables, means for twisting the fibers from said creel bobbins onto the strand being formed from the fibers drawn from the respective table means, and means for controlling the twist in the fibers of said outer covering layer relative to the respective twists imparted to the core and the intermediate layers laid thereon so that the twist in the layers from the core to the outermost covering layer of the strand is progressively decreased so that in the finished strand the respective fibers of the core and the succeeding layers are substantially equal in length for insuring that each of the strand fibers are uniformly stressed under given load conditions.

3. In a machine for making rope strand which includes a core, at least one intermediate layer and an outermost covering layer, the improvement comprising a plurality of rotatably mounted table means, each having bobbins containing the fibers which form the core and the intermediate layer respectively, and a stationary creel with bobbins containing the fibers forming the outermost covering layer, means for drawing the fibers from the respective bobbins whereby the fibers drawn from the bobbins of the table means forming the core of said rope strand are drawn through the next table means so that the fibers drawn from the latter are laid onto the core fibers drawn from the former table means to form the intermediate layer thereon, means for rotating each of said table means to impart a twist to the respective fibers being drawn therefrom, means for twisting the fibers drawn from said creel bobbins onto the intermediate layer of said strand, means for individually controlling the speed and relative direction of rotation of the respective table means, and means for controlling the twist in the fibers of said outermost covering layers relative to the respective twist imparted to the core and intermediate layer so that the twist of the respective layers from the core to the outermost layer making up the rope strand is progressively decreased so that in the finished strand the respective fibers making up the strand are substantially equal in a unit length of said strand to insure each fiber being uniformly stressed under a given load condition.

4. The invention as defined in claim 3 wherein said table means includes inner, outer and intermediate plate members coaxially disposed in horizontally spaced relation for securing .the'rebetween two rows of bobbins, means for maintaining said plates in spaced relationship, and guide means for directing the fibers drawn from its respective bobbins through the center of said table means.

5. A table unit for use in a rope making apparatus comprising a pair of spaced support stanchions, each having a bearing support at its upper end, a bearing having a bore extending therethrough journaled in each of said bearing supports, a table forming plate connected to each said respective bearing, an intermediate plate spaced between said table forming plates, means for connecting said plates vertically in horizontally spaced coaxial relationship, a row of bobbins connected between adjacent plates, means for guiding the fibers drawn from the respective bobbins through the center of said plates, and means for rotating said table plates and bobbins carried thereon as a unit about said horizontal axis for imparting a twist to the fibers being drawn therefrom.

6. In a machine for making rope strand which includes a core, at least one or more layers layed onto said core comprising a plurality of table means, each of said table means including a pair of spaced support stanchions, each having a bearing support at its upper end, a bearing having a bore extending therethrough journaled in each of said bearing supports, a table forming plate connected to each of said respective bearings, an intermediate plate spaced between said table forming plates, means for connecting said plates in horizontally spaced coaxial relationship, a row of bobbins connected between adjacent plates, means for guiding the fibers drawn from the respective bobbins through the center of said plates, and means for rotating said table plates and bobbins carried thereon about said horizontal axis for imparting a twist to the fibers being drawn therefrom, and a stationary creel with bobbins containing the fibers for forming the outermost covering layer, means for drawing the fibers from the respective bobbins whereby the fibers drawn from the bobbins of one of the table means forming the core of said rope strand are drawn through the next table means so that the fibers drawn from the latter are laid onto the core fibers drawn from the former table means to form the intermediate layer, means for rotating each of said table means to impart a twist to the respective fibers being drawn therefrom, means for twisting the fibers drawn from said creel bobbins onto the intermediate layer of said strand, means for individually controlling the speed and relative direction of rotation of the respective table means, and means for controlling the twist in the fibers of said outer covering layer relative to the respective twist imparted to the core and intermediate layer so that the twist of the respective layers from the core to the outermost cover layer making up the rope strand is progressively decreased so that in the finished strand the respective fibers making up the strand are substantially equal in a unit length of said strand to insure each fiber being uniformly stressed under a given load condition.

References Cited by the Examiner UNITED STATES PATENTS 23,785 4/1859 Rinek 57-l5 1,210,001 12/1916 Randall 57- 15 1,767,693 6/1930 Morin 5715 2,098,922 11/1937 McKnight 5715 X 2,106,803 2/ 1938 Johnson et al 5759 2,111,630 3/1938 Johnson et a1. 57-15 2,281,111 4/1942 Robinson et al 5715 X 2,659,192 11/1953 Ripley 57 15 X 2,981,049 4/ 1961 Crosby et a1 5714 X 3,097,472 7/1963 Stirling 57-l15 3,140,576 7/1964 Ha-ugwitz 5713 MERVIN STEIN, Primary Examiner.

J. PETRAKES, Assistant Examiner. 

1. A MACHINE FOR MAKING ROPE STRAND COMPRISING A PLURALITY OF TABLE MEANS, EACH OF SAID TABLE MEANS HAVING A BEARING SUPPORT WITH A BORE EXTENDING THERETHROUGH, MEANS FOR ROTATABLY JOURNALING EACH OF SAID TABLE MEANS IN COAXIAL ALIGNMENT, A PLURALITY OF BOBBINS HAVING FIBER WINDINGS THEREON MOUNTED ON EACH OF SAID TABLE MEANS, EACH OF SAID TABLE MEANS INCLUDING MEANS FOR GUIDING THE FIBER FROM ITS RESPECTIVE BOBBINS THROUGH THE BORE IN THE BEARING SUPPORT THEREOF, MEANS FOR DRAWING THE FIBERS THROUGH THE BORE OF THE RESPECTIVE BEARING SUPPORTS SO THAT THE FIBERS DRAWN FROM ONE TABLE MEANS ARE LAID ONTO THE FIBERS DRAWN FROM THE NEXT PRECEDING TABLE MEANS, MEANS FOR ROTATING EACH OF SAID TABLES TO IMPART A TWIST TO THE FIBERS BEING DRAWN FROM THE RESPECTIVE BOBBINS SO THAT THE FIBERS DRAWN FROM ONE OF SAID TABLES ARE TWISTED TO FORM THE CORE OF SAID STRAND, AND THE FIBERS DRAWN FROM SAID OTHER TABLES ARE TWISTED IN SUCCESSIVE CONCENTRIC LAYERS UPON SAID CORE, MEANS FOR INDIVIDUALLY CONTROLLING THE RELATIVE ROTATION AND DIRECTION OF ROTATION OF THE RESPECTIVE TABLE MEANS WITH RESPECT TO ONE ANOTHER TO CONTROL THE PITCH AT WHICH THE FIBERS DRAWN FROM THE BOBBINS OF THE RESPECTIVE TABLES ARE TWISTED PER UNIT LENGTH OF ROPE STRAND FORMED THEREBY, A STATIONARY CREEL MEANS, A PLURALITY OF CREEL BOBBINS CONTAINING THE FIBERS FOR FORMING THE OUTERMOST COVERING LAYER MOUNTED ON SAID STATIONARY MEANS, MEANS FOR TWISTING THE FIBERS FROM SAID CREEL BOBBINS ONTO THE STRAND BEING FORMED FROM THE RESPECTIVE TABLE MEANS, AND MEANS FOR CONTROLLING THE TWIST IN THE FIBERS OF SAID OUTER COVERING LAYER RELATIVE TO THE RESPECTIVE TWISTS IMPARTED TO THE CORE AND THE INTERMEDIATE LAYER LAID THEREON SO THAT THE TWIST IN THE LAYERS FROM THE CORE TO THE OUTERMOST COVERING LAYER OF THE STRAND IS PROGRESSIVELY DECREASED SO THAT IN THE FINISHED STRAND THE RESPECTIVE FIBERS OF THE CORE AND OF EACH SUCCEEDING LAYER ARE SUBSTANTIALLY EQUAL IN LENGTH FOR INSURING THAT EACH OF THE FIBERS ARE UNIFORMLY STRESSED UNDER GIVEN LOAD CONDITIONS. 